Internal combustion engine



2 mw. F

June 29, 1965 D. l. BRAHLER INTERNAL coMBusTIoN ENGINE Filed NOV. 15,' 1965 United States Patent 3,191,584 Y INTERNAL COMBUSTION ENGINE Dean I. Brahler, 23 Walden Road, Rochester, N.Y. F led Nov. 13, 1963,` Ser. No. 323,472 1 Claim. (Cl. 12B-50) This invention relates to internal combustion engines and particularly to an improvement including a pair of pistons reciprocal in opposing directions and coactiveto drive a crank shaft in one direction; more specically, my improvement comprises an internal piston slidably mounted Within an external piston in turn slidable in a cylindrical chamber in an engine block. It is a significant object ofmy invention to provide an improved engine of vthe above` described construction. While the advantages of providing a double piston movable in opposite directions for driving la single cam shaft in one direction have been recognized, such prior constructions have not been satisfactory.

All prior known constructions utilizing the double piston have been awkward, unsatisfactory constructions, therefore, it is a principal object of my invention to provide an improved and simplified construction of a double Ypiston arrangement which more satisfactorily balances the driving force exerted on the cam shaft driven off of the pistons, thereby reducing vibration and increasing efficiency of the engine. 1.

One advantage of my construction is the provision of a precompression chamber into which fuel mixture is admitted during a compression stroke of the pistons and where the fuel -is precompressed during combustion. At the end of the combustion stroke, the precompressed fuel facilitates the exhaust of the burned fuel in the compression-combustion chamber.

It is a further object of my invention to provide a novel combination of means for applying the power exerted on the crankshaft with each combustion stroke whereby simultaneous opposing thrusts are exerted on the crank shaft in an improved simplified manner over that previously known.

It is a further object of my invention to provide an improved internal combustion engine of the above described nature having a precompression chamber.

Other objects and advantages of my invention will be particularly set forth in the claim and will be apparent from the following description, when taken in connection with the accompanying drawings, in which:

FIG. 1 is a sectional view of one embodiment of my invention with parts broken away; and

FIG. 2 is an enlarged end elevational view of a set of double pistons removed from the FIG. 1 embodiment of my invention with parts broken away.

With reference to the figures, I have chosen to illustrate my invention in the environment of a two cycle engine, as will be described below. It will be understood that the concept of my invention is applicable to other known types of internal combustion engines. t

In FIG. 1, I have diagrammatically illustrated a carburetor selectively feeding a fuel and air mixture through suitable distribution channels in an engine head 12 and through reed valves 14 to piston cylinders or cylindrical chambers, generally indicated by thenumerals 16 and 17, formed in the engine block 18. Chambers or piston cylinders 16 and 17 each comprise a smaller in diameter portion 20 and a larger in diameter portion 22 formed at the top thereof and functioning as a precompression chamber as described below.

An outer cylindrical piston 24 is slidably sealed to the internal sidewalls of the smaller diameter portion 20 of each of the cylindrical chambers 16 and 17 in the conventional manner, as for example, by suitable piston rings 26 seated in circumferential grooves in the external sidewalls of pistons 24.

Each of the outer pistons is provided with an internal cylindrical bore or chamber adapted to receive an inner cylindrical piston 30. Each of the pistons 30 is sealed to the sidewalls of the internal bore 28 of the cylindrical piston 24, in the conventional manner, as for example, by suitable piston rings 32 seated in circumferential grooves in the external circumference of inner cylindrical piston 30.

A pair of connecting rods 34 are each pivotally connected at their upper ends to opposing sides of each of the outer cylindrical pistons 24 by pins 36. Each of the rods 34 is rotatably mounted at their lower ends to a crankshaft 38 in the conventional manner. A connecting rod 40 is pivotally mounted at its upper end to each of the inner pis-tons 30 by a pin 42 passing transversely through the piston 30, and each of the rods 40 is rotatably mounted at its lower end to the crankshaft 38 in the conventional manner, as illustrated in the drawings. Crankshaft 38 is rotatably journalled in a pair of bearings 44 fitted into horizontal bores 46 provided in the sidewalls of the crankcase portion of the engine block 18. A conventional oil sump 49 for lubricating the moving parts above described is provided in the crankcase of the engine block.

In the center of the engine block 18, I provide a horizontal exhaust bore 48 extending between and common to the two cylindrical chambers or piston cylinders 20. Exhaust fuel passes from the horizontal bore 48 to an intersecting horizontal bore 50 extending to atmosphere.

A pair of spark plugs 56 are mounted in a conventional manner within horizontal holes or bores 54 provided in the engine block 18. Spark plug holes S4 extend between each of the smaller in diameter portions 20 of the piston cylinders 16 and 17 and horizontally disposed Vinwardly tapering bores 52. o

There are a plurality of radial openings or ports 58 provided at the top or inner end of each of the outer cylindrical pistons 24. There are a plurality of radial downwardly sloping slots 59 cut out of the side walls of piston cylinders 20 which communicate between piston radial ports 58 and precompression chamber 22 when the pistons 20 are at the end of a combustion stroke and the beginning of a compression stroke as illustra-ted in FIG. l by the right hand pair of pistons in cylinder 16. In this position, fuel is transferred from the larger diameter precompression chamber 22 through radial slots 59 and radial ports 58 into a compression and combustion chamber generally indicated by the numeral 60 and defined by the interior sidewalls 28 of the cylindrical piston 24 and the upper surface of the piston 30. In this position, an exhaust port 62 through the outer cylindrical piston 24 communicates between compression chamber 60 and exhaust bore 48.

As the outer cylindrical piston 24 makes a downward compression stroke, the inner piston 30 makes an upward compression stroke, the upper two sealing rings 26 seal the radial ports 58 from the precompression chamber 22 while the sealing rings 32 of piston 30 seal the compression chamber 60 from the exhaust port 62 when piston 30 makes its upward stroke past the port 62. l

During the compression stroke, the outer piston 24 and inner piston 30 travel from the exhaust position above described to the ignition position illustrated by the left hand pair of pistons in piston cylinder 17. In this latter position, the two uppermost sealing rings 26 seal the radial ports 58 in communication with the spark plug 56 at which position ignition occurs and the combustion or power stroke follows during which the pistons 24 and 30 are returned to the exhaust position illustrated in the right hand piston cylinder 16. Ignition of the fuel occurs as the cranks pass over deadcenter on the crank cycle.

.er stroke .while the outer cylindrical piston 24 travels upwardly. Thereafter the precompressed fuel is admitted ythrough the ports 5S to the compression chamber 60 as described above. ,At the end ofthe combustion stroke, the exhaust of burned fuel through exhaust port 48 is facilitated by the precompressed fuel mixture entering theV compression chamber 60 through the radial ports 5S. Y

One advantage. of my invention `particularly with regard to a two cycle engine is that, unlike known two Cycle engines, this construction has a wet sump 479 in which there is oil for lubricating the moving parts, so it is not necessary for the oil to be introduced with the fuel.

This type of a two cycle construction has approximately half the number' of moving parts of normal four cycle engines, eliminating the cam shaft and tappet valves generally used. It does not require thenormal fuel transfer tubesfor present two cycle engines. The compressed gas passing from' the precompression chamber ZZ'into the compression and combustion chamber 6i? assures greater volumetric efiiciency.

While I vhave shown and described the preferredform 0f mechanism of my invention it will be apparentjthat various modifications and changes Vmay be made therein,

f particularly in the form and relation of parts, without departing from the spirit of my invention as set forth in the appended claim.v

I claim:

ln combination, an engine having a piston cylinder deiining a irst chamber oney end of which defines an enlarged annular precompression chamber having ardiameter greater than said cylinder and which communicates through a valve to a source of fuel; a first piston slidably 'sealed within said chamber, said piston having an internal compression chamber slidably receiving a second piston in sealed relationship with the sidewalls of said compression chamber; means interconnecting said pistons for reciprocating saidpistons in opposing directions within said iirst chamber; and fuel transfer means communicating between said compression lchamberand said first chamber in vfuel transfer relationship only when said pistons are at substantially the end of a combustion stroke, said fuel transfer means including a plurality of radial ports in an inner end of said first piston; means sealing said ports from said precompression chamber except when substantially at the end of ysaidl combustion stroke; and a plurality of radial vertical kslots formed in the sidewalls of said piston cylinder sloping downwardly from the sidewalls of said enlarged annular chamber and communicatingwith said ports when said first piston is at substantially the end of said combustion stroke.

References Cited by the Examiner UNITED STATES PATENTS'- FRED E. ENGELTHALER, Primary Examiner. 

